Torsion meter



Jan. 5 1926.

R. CHILTON ET Ax.

TORSION METER Filed Sept. 5, 1923 2 Sheds-Sheet 1 Amm/virv Jan. 5 1926.1,568,544

R. CHILTON ET AL TORSION METER INVEIVTRS A TTORNEY Patented Jan. 5,-1926.

UNITED lSTATES PATENT orrlcrs.

ROLAND CHILTON AND FRANK A. HAYES, 0F KEYPORT, NEW JERSEY, ASSIGNORS T0AEROMARINE. PLANE & MOTOR COMPANY, A CORPORATION 0F NEW YORK.

.TORSION METER.

Application led September 5, 1923. Serial No. 661,085.

To all whom 'it may concern:-

Be it known that we, ROLAND CHILTON, a subject of the King of England,and FRANK A. HAYES, a citizen of the United States, and both residentsof Keyport, in the county of Monmouth and State of New Jersey, haveinvented certain new and useful Improvements in Torsion Meters, of whichthe following is a specification, reference being had to theaccompanying drawings, forming part of this specification.

This invention relates to improved means for obtaining visual andgraphic records of the relative angular motion between two parts of arotatingsystem. More specifi- (ally, the invention contemplates animproved means for obtaining visual indication or graphically recordeddiagrams representing to accurate scale the torque deflections in ashaft system.

As with torsion meters in the prior art, the apparatus ofthis-disclosure can be used either to indicate the relative motionbetween the two points of a system to which the two elements of thedevice are connected, or between one point of a rotating system and a.member rotated at uniform speed, such as a yieldingly driven fly-wheel.

The method of connecting the rotational elements of the torsional meterto the points of the shaft system whose relative behavior is to bestudied is not in itself a part of this invention, the principal objectof which is to aii'ord simple and accurate mea-ns for 0btaining a polardiagram representing accurately to scale small relative oscillationsbetween two members which are rotating at the same average speed. Thepresent invention aims .at being especially useful in `the case where ashaft is subject to high frequency torque variations which result incyclic torsional deflections during each revolution. Multiple cylinderengine crankshafts are a case in point, and in the drawings theapplication of this invention to such an engine is illustrated.

Many of the torsion meters of the prior lart are adapted to measure theaverage torsional defiection on a shaft, and while the present inventioncan be used for this purpose, it is intended t0 be primarily adapted toshow in addition, the actual frequency and amplitude of torsionalvibrations occurring in each revolution. In the case where an indicationof average deiiection or torque is required, mechanical or electricalconnection means for obtaining a stationary diagram from the relativebehavior of the rotating parts can be used since the damping effects ofsuch apparatus are in that case advantageo'us. On the other hand, whenit is desired to accurately measure the torsional vibrations no dampingor inertia effects or lost motion can be permitted in theA stant radius,i. e., circular, when the deection is constant, and will vary inwardlyand outwardly from this reference circle 1n sympathy with the variationsin torque.

To these and other ends,the invention consists in certain improvementsand the combination and arrangements of parts, all as will be more fullyhereinafter described, the features of novelty being pointed outparticularly in the claims at the end of the speciications. l

In the drawings Figure 1 is a perspective view of an internal combustionengine showing the present invention as applied thereto.

Figure 2 is a vertical section taken on thef'line 2 of Fig. 3 andillustrates a modification of the form shown in Fig. 1.

Figure 3 is a fragmentary end view of the form shown in Fig. 2. 0

Figure 4 graphically illustrates a v1sualization of cyclic torsionaldeiiections in a drive shaft as would be seen by using either one of theforms shown in Figs. 1 and 2.' l

Figure 5 is a vertical section taken on the line 5--5 of Fig. 6 showinga further modification of the form shown in 1.

Figure 6 is an end view of F1g. 5.

Figure 7 graphically illustrates a visualization of torsionaldeflections of a driven shaft as observed by the use of the. forms shownin Figs. 5 and 6.

Figure 8 is a side elevation on an enlarged scale of the form shown inFig. l illustrating the manner in which a permanent graphic record canbe obtained by photography of torsional deflections in a sha t Figure 9is an end view of the device showing a scale attached thereto for thepurpose of measuring the polar coordinates of the path of travel of apoint of light.

In -the present instance with reference to Fig. 1, 1() designates amultiple cylinder engine, 11 the crankshaft thereof to one end of whichthere is a sprocket wheel 12.

Secured to the crankcase 13 in any suitable manner and adjacent anopening 14 therein,.is a preferably cylindrical'- open ended casing 15which is provided with an integral sleeve portion 16.

lAn extension shaft 17 is attached to the crankshaft 11 and projectsthrough the opening 14, said shaft 17 is rotatable within the sleeve 16and is provided with a circular disk 18 at its extreme outer end. In.this disk 18 there is formed a curved slot 19.

A hub 21 having a sprocket portion 22 ,is rotatably mounted on thesleeve .16. and is provided with a circular disk 23 disposed adjacent tothe disk 18. In this disk there is formed a radial slot 24 which 1sdisposed in its assembled relation so as to intersect the curved slot 19approximately intermediate the two ends thereof.

A lay shaft 25 is mounted on the standards 26 in a position parallel tothe crank shaft 11 and is provided on either end with sprocket wheels 27and 28, the sprocket 28 being driveably connected by a chain 30 to thesprocket 12 of the shaft 1l, the sprocket 27 0n the other end of theshaft' 25 being connected by a chain 31 to the sprocket portion 22 ofthe hub 21.

It will be readily understood from the foregoing description and withreference to Fig. 1 that the disk 18 will be rotated directly by theextension shaft 17, whereas the disk 23 will be rotated from the otherend of the crankshaft 11 by means of the lay shaft 25, consequently, iftorsional deflections occur inthe crankshaft 11 there will be relativemovement between the two ends of the shaft, which will result inrelative movement between the disks 18 and 23, causing the point ofintersection of the slots t-o move radially inward or outward. v

If the disk 23 is provided with a radial slot as before stated, and thecurved slot in disk 18 has the form of an Archimedean spiral, then theradial movement of the point of intersection will be proportionate tothe relative angular deflection of disk 18 with respect to disk 23.Hence although the slots in disks 18 and 23 may be given F any desiredform provided only that they intersect each other within the range ofthe instrument it is advantageous to make these slots respectivelyradial and of the spiral form described.

It will be further understood that when the interior of the case isilluminated as by the lamps 32 the point of intersection of the slotswill be brightly illuminated while the general surfaces of the disks arepreferably of dark color. The resulting point of light will moveradially inwardly and outwardly in sympathy with the relative motionbetween the two adjacently disposed disks 18 and 23. In normal use thedisks will be rotating lat relatively high speed and as hereinbeforementioned, owing to the persistence of vision, the point of light willappear to the eye of the observer as plotting a continuous path such asis indicated by the broken line 33 in Figure 4, wherein the line 34indicates the base circle. In this manner a visual polar diagram ofcyclic torque deflections in a shaft system is obtained. The diagramsillustrated are those which will be obtained from a shaft exhibitingthree cyclic torsional vibrations per revolution.

With reference to Figs. 2 and 3 there is shown a modification of theform shown in Fig. 1 and in which thel two disks 18 and 23 areindividually driven as described in the foregoing from either end of thecrank-l shaft. In this particular showing the hub 21 is provided with anannular insulated portion 36 in which is embedded a conductive slip ringor contact member 37 and on which bears a brush or conductor 38. Thedisks are provided each with an opening 39 and 40 respectively, saidopenings being in axial alignment with each other in assembled relation.In the opening 40 there is secured insuitable insulated portions 41 'anelectrically conductive rod or wire 42 which is connected to ring 37 byany suitable means conductive of electricity as 43, said Wire 42 beingdisposed radial of the axis of rotation.

In the opening 39 of the disk 18 there is secured a rod or wire 44disposed adjacent to the wire 42 and at an angle thereto as shown inFig. 3 so that the two wires will intersect with a slight gap orclearance therebetween. It will be readily understood by those skilledin the `art that when a high tension current used in connection with asuitable interrupter passes through a conductor 45 to the brush 38 andthence to the wire 43, a spark will jump from the wire 42 to the wire 44at CTI the intersection of the two wires, it being assumed that the wire44 is properly grounded.

This spark will travel radially inwardly or outwardly when relativemotion takes place between the two discs, forming a path of lightsimilar to that shown in Fig. 4, and substantially the same as producedby the device in Fig. 1.

Referring to Figures 5 and 6 there is shown a further modification, inwhich 50 designates a fixed member, 51 a sleeve portion thereon, 52 theextension shaft rotatable in the sleeve 51, a hub 53 having a sprocket54 is driven from the lay shaft 25 and a disk 55 is rotatably mounted onthe sleeve 51. An annular member 56 composed of insulating material hasa conducting ring 57 imbedded therein on `which bears a brush 58. Aspark point 59 is secured in an insulated portion 60 of disk 55 and issuitably connected to the ring 57. A member 61 having a spark point 62is pivotally mounted on the disk 55 in a manner so that under normalconditions a small gap will exist between the points 59 and 62. Themember 61 is so positioned on the disk that the point 62 will swing asnearly radial as possible to the axis of rotation of the disk 55.

To the shaft 52 there is secured an arm 63 having a 'slot 64 connectingwith a pin 65 in the member 61. A spring 66 is provided to counteractany back lash effect on the pivoted member 61.

It is apparent that when there is a deflection in the crankshaft towhich this particular device is applied there will be a relative motionbetween the disk 55 and the arm 68 which will result in the spark point62 being moved inwardly and outwardly past' the point 59 lto positionssuch as shown in broken lines, thus increasing or decreasing the gapl inproportion to the deflection of the shaft. With this last mentionedconstruction, and assuming that the device is connected to a suitablesource of current, a varying short or long spark will result on eitherside of a base circle 67, Fig. 7 forming a relatively broad path oflight 68 as distinguished from that of Fig. 4.

The particular formation or contour of the path of light asdiagrammatically shown in both Figs. 4 and 7 would result only fromdeflections having three cycles per revolution, and is given merely asan example of a reading with one .form 'of crankshaft.

. In Fig. 8 we have shown a means by which a permanent record may beobtained for future reference by photography and in which a piece ofground glass 70 can bev interposed between the lamps 32 and the disks18, or between the disks and the camerav 71. A piece of sensitized papermay be used in lieu of the camera, said paper being clamped against'theflange 72of the casing 15 in any convenient manner.

With reference to Fig. 9 there is shown .a means for measuring thepathfof travel of a point of light, or for ascertaining the extent ofdeviation of said light from a given oint or base circle. The annularmember 5 composed of relatively light sheet material and having a scaleportion 76 can be secured in the casing 15 and against the flange 72 inany convenient manner as by frictional engagement.

A suitable reflector may be provided within the casing 15 to projectthelight from the aperture in the disks.

Variations may be resorted to within the Scope of the invention, andportions of the improvements may be used without the others.

Having thus ldescribed our invention, we

claim,

1. In apparatus of the class described, a casing, a pair of membersmounted for rotation within the casing and for relative movement to eachother, an illuminant within the casing, and means on said members forproducing a spot of light for rotation with said members and for movingsaid spot radially in sympathy with relative motion between the members.

2. A torsion meter for a rotating shaft including means for producing abeam of light rotating parallel to an axis, means for moving the beamradially of the axis in sympathy with the deflection of the shaft,

Vin combination with means for recording the path plotted by said beam.

3. In a device for obtaining visual indication of torsional 4deflectionsin a shaft system, a pair of members rotated each from different point-sof the shaft system. a means operative by relative motion of saidmembers induced by torsional deflections in the shaft to move a point oflight rotating with the members radially in and out of a base circle. l

4. In a device for obtaining graphic records of torsional deflections ina shaft system, a pair of members rotated from sepa-v rate points on theshaft system, means operative by relative motion of said members inducedby torsional deflections in the shaft to project a rotating beam oflight parallelV to axis of rotation and to move the same radially in andout of a base circle, in combination with means for recording the pathof the light so projected.

5. The combination with a powermeans having a drive shaft, of a casingfixed adjacent one end thereof, a first disk mounted in the casing anddrivably connected to the end of the shaft. a second disk mountedadjacent the first disk and drivably connected to a remote part of theshaft, elongated llO apertures in both of said disks so disposedrelatively as to cause an intersection thereof, and means within thecasing adapted to illuminate the intersection of said aperturescontinuously throughout their revolution.

6. In the art of visualizing torsional deflections in a shaft system, afixed casing, a pair of adjacent disks rotatably mounted in said casingand respectively driven from divers points of the shaft in a manner sothat a defiection in the shaft will cause relative angular motionbetween said disks, elongated means associated with each of said disksso disposed relatively to one another as to cause an intersectionthereof, means adapted to create a luminous spot at the intersection ofthe elongated means, said luminous spot rotating about the axis of theshaft and moving radially thereof in harmony with torsional deiiectionstherein.

7. In a device of the class described, the combination with an internalcombustion engine having a drive shaft, of a casing secured to saidengine and disposed adjacent one end of the shaft, a pair of disksrotatably mounted Within the casing` and driven from either end of theshaft respectively,

illuminating means within the casing, elongated apertures in said disksso disposed relatively to one another as to cause an intersectionthereof, means for illuminating said point of intersection throughout acomplete revolution.

8. In a device for producing a visible indication of deflections in adrive shaft, a drive shaft, a pair of adjacent members individuallydriven from divers portions of the shaft and adapted for relativeangular movement, an illuminant, a means associated With both of saidmembers and coacting with said illuminant to produce a closed polardiagram radially varying in accordance to deflections in the shaft.

9. In a device for producing a visible indication of deflections in adrive shaft, a drive shaft, a pair of adjacent members individuallydriven from divers portions of the shaft and adapted for relativeangular movement, an illuminant, a means associated with both of saidmembers and coacting with said illuminant to plot a luminous annulusdiagrammatic of deflections in the shaft upon rapid rotation of themembers.

10. In the art of measuring the torque load of a drive shaft, thecombination with a drive shaft, of a casing fixed adjacent the shaft, apair of members in said casing rotated individually therein throughdriving -means associated With different portions of the shaft, saidmembers so mounted as to permit of relative movement, a slot in each ofthe members, said slots being so disposed as to intersect one another toform an aperture, a means for illuminating the interior of said casingso as to constantly cause a light to issue from said aperture.

ll. In apparatus of the class described, in combination, a shaft to betested, a casing fixed adjacent one end thereof, a portion of the shaftextending into said casing a lfirst disk secured to the shaft, a slot inthe disk, a second disk rotatably mounted on'a portion of the casing andadjacent to the first disk, a substantially radial slot in the disk, theslot of the first disk disposed so as to intersect the radial slot toform an aperture, a means for rotating the second said disk from aremote portion of the shaft, and means for constantly illuminating theintei-section of said slots from the interior of said casing.

12. In apparatus of the class described, the combination with a driveshaft to be tested, of a casing fixed adjacent one end thereof, a firstdisk member rotatably mounted in the casing and operated directly fromsaid shaft, asecond disk mounted in said casing in a manner as to permitof it being rotated relatively to the first said disk, a lay shaftdriven from a remote portion of the shaft and adapted to drive thesecond said disk, one or more elongated apertures in each of said disksso disposed relatively that the apertures of one disk intersect those ofthe other, illuminating means within the casing adapted to constantlyilluminate the intersection of said apertures during their travel.

13. In apparatus of the class described, the combination With a driveshaft to be tested for cyclic torsional deflections, of a casing fixedadjacent one end thereof, a first disk member rotatably mounted in thecasing and operated directly from said shaft, a second disk memberrotatably mounted in said casing and adjacent to the first disk, a powertransmitting means driven from a remote portion of the shaft and adaptedto drive the second said disk, elongated apertures in each of said disksso disposed relatively that the apertures of one disk intersect those ofthe other, means within the casing adapted to constantly illuminate theintersection of said apertures, the Whole so organized that the rapidrotation of the disks from remote portions of the drive shaft will causea visible manifest-ation in the form of a closed polar diagram of cyclictorsional deflections in the drive shaft.

Signed at Keyport in the county of Monmouth and State of New Jersey this31st day of August A. D. 1923.

ROLAND CHILTON. FRANK A. HAYES.

